Engstrom et al. demonstrate that spatial transformations such as translations and rotations can be used to generate adversarial examples. Personally, however, I think that the paper does not address the question where adversarial perturbations “end” and generalization issues “start”. For larger translations and rotations, the problem is clearly a problem of generalization. Small ones, can also be interpreted as adversarial perturbations – especially when they are computed under the intention to fool the network. Still, the distinction is not clear ...